The present invention relates to methods and apparatus for rotating a substrate and, more particularly, to such methods and apparatus providing gas driven rotation to the substrate.
Silicon carbide (SiC) is increasingly recognized as an effective semiconductor material for electronic devices. SiC possesses a number of properties that make it particularly attractive for applications requiring devices to operate at high temperature, power and/or frequency. SiC exhibits highly efficient heat transfer and is capable of withstanding high electric fields.
It has been demonstrated that hot-wall chemical vapor deposition (CVD) reactors can provide epitaxial layers of SiC with morphology and doping superior to cold-wall systems. See, for example, U.S. Pat. No. 5,695,567 to Kordina et al., the disclosure of which is hereby incorporated herein by reference. It has further been demonstrated that the addition of substrate rotation to a hot-wall CVD system may improve both the per cycle capacity of the system and the uniformity of the epitaxial layers obtained. U.S. Pat. No. 4,860,687 to Frijlink discloses a device comprising a flat susceptor rotating parallel to a reference surface. The device disclosed therein may be used in a vapor phase epitaxy system.
According to embodiments of the present invention, a gas driven rotation apparatus for use with a flow of drive gas includes a base member having an upper surface, a main platter overlying the upper surface of the base member, and a satellite platter overlying the main platter. The apparatus is adapted to direct the flow of drive gas between the upper surface of the base member and the main platter such that the main platter is rotated relative to the base member by the flow of drive gas. At least a portion of the flow of drive gas is directed from between the upper surface of the base member and the main platter to between the main platter and the satellite platter such that the satellite platter is rotated relative to the main platter by the at least a portion of the flow of drive gas.
According to further embodiments of the present invention, a gas driven rotation apparatus for use with a flow of drive gas includes a base member having an upper surface and a main platter having an upper surface and overlying the upper surface of the base member. At least one generally radially extending, substantially straight satellite drive channel is formed in the upper surface of the main platter. A satellite platter overlies the main platter and the at least one satellite drive channel. The apparatus is adapted to direct at least a portion of the flow of drive gas through the satellite drive channel to rotate the satellite platter relative to the main platter about an axis of rotation.
According to further embodiments of the present invention, a gas driven rotation apparatus for use with a flow of drive gas includes a base member having an upper surface, a main platter overlying the upper surface of the base member, and a satellite platter overlying the main platter. The apparatus is adapted to rotate the main platter relative to the base member in a first direction. The satellite platter is rotated relative to the main platter in a second direction opposite the first direction. At least one of the rotation of the main platter and the rotation of the satellite platter is driven by the flow of drive gas.
According to method embodiments of the present invention, a method for rotating an article includes providing a gas driven rotation apparatus including a base member having an upper surface, a main platter overlying the upper surface of the base member, and a satellite platter overlying the main platter. The article is placed on the satellite platter. A substrate is placed on the satellite platter. A flow of drive gas is directed between the upper surface of the base member and the main platter such that the main platter is rotated relative to the base member by the flow of drive gas. At least a portion of the flow of drive gas is directed from between the upper surface of the base member and the main platter to between the main platter and the satellite platter such that the satellite platter is rotated relative to the main platter by the at least a portion of the flow of drive gas
According to further method embodiments of the present invention, a method for rotating an article includes providing a gas driven rotation apparatus including a base member having an upper surface, a main platter overlying the upper surface of the base member, and a satellite platter overlying the main platter. The article is placed on the satellite platter. The main platter is rotated relative to the base member in a first direction. The satellite platter is rotated relative to the main platter in a second direction opposite the first direction. At least one of the rotation of the main platter and the rotation of the satellite platter is driven by a flow of drive gas.
Objects of the present invention will be appreciated by those of ordinary skill in the art from a reading of the Figures and the detailed description of the preferred embodiments which follow, such description being merely illustrative of the present invention.